What happened
ChatGPT's market share fell to 46% by May 2026, dropping below 50% for the first time in March, per Sensor Tower's "State of AI 2026" report. Google Gemini captured 28% of the market, with Claude reaching 10%. Despite this shift, ChatGPT became the fastest application to reach one billion monthly users in May. The report also noted Grok users are four times more likely to be crypto traders, while Claude achieved a higher average revenue per U.S. mobile user at $2.76, compared to ChatGPT's $1.74, and a 13% subscription conversion rate.
Why it matters
AI assistant market dynamics are shifting from raw user acquisition to monetisation and targeted user engagement. Procurement teams and founders evaluating AI tools must now prioritise factors beyond overall user numbers, considering specific use-case alignment and revenue efficiency. Claude's higher average revenue per user and subscription conversion rate demonstrate that a smaller, engaged user base can yield greater financial returns. This indicates that distribution advantages, such as Gemini's integration across Google's ecosystem, and brand trust, which influenced user migration to Claude following OpenAI's Department of Defence partnership, are increasingly critical competitive differentiators.
